492 VEGETABLE DRUGS 



Habitat. — Southern Europe and Asia; cultivated in 

 temperate climates. 



Description. — About 1 Mm. in diameter, almost globular, 

 with a circular hilum; testa blackish-brown or grayish- 

 brown, finely pitted, hard ; embryo oily, with a curved 

 radicle and two cotyledons, one folded over the other ; free 

 from starch ; inodorous when dry, but when triturated with 

 water, of a pungent, penetrating, irritating odor ; taste 

 pungent and acrid. 



Constituents, — 1, a glucoside, sinigrin (or potassium 

 myronate), and a ferment, my rosin. In the presence of water 

 the latter converts the former into the acrid, volatile, official 

 oil of mustard (allyl sulphocyanide, C3H5CNS), acid potas- 

 sium sulphate, and glucose ; 2, a fixed, bland oil, similar to 

 that in white mustard ; 3, gum. 



Dose. — Same as white mustard. 



Commercial form of mustard is a mixture of black and 

 white mustard. 



PREPARATION. 



Oleum Sinapis Volatilp. Volatile Oil of Mustard. 



Synonym. — Oleum sinapis, B.P.; allyl sulphocyanide 

 (C3H5CNS), oleum sinapis 8ethereum,E.; essence de moutarde, 

 Fr.; aetherisches senfol, G. 



Derivation, — A volatile oil obtained from black mustard 

 by maceration with water and subsequent distillation. 



Properties. — A colorless or pale yellow, limpid and 

 strongly refractive liquid, having a very pungent and acrid 

 odor and taste. Freely soluble in alcohol, ether, or carbon 

 disulphide, the solutions being neutral to litmus paper. 

 Spec. gr. 1.018 to 1.029. 



Action External. — Mustard quickly dilates the vessels of 

 the skin and causes hyperaemia. If its application is 

 frequently repeated, there is so much vascular irritation that 

 transudation of serum occurs under the epidermis, and 

 blisters or even pustules are formed. Mustard induces a 

 sensation of burning in man, but is not so irritating as oil 



